Electrochemical study on Bronze biocorrosion: The effect of microstructure

In this study the behavior of a 12wt% Sn bronze was analyzed in presence and absence of bacteria in a controlled solution containing chlorides, nitrates, sulfates and carbonates in order to simulate stagnant conditions. Biocorrosion processes were studied through potentiodynamic measures (anodic curves) evaluating the effect of the microstructure (as cast or recrystallized). The use of Electrochemical Impedance Spectroscopy (EIS) allowed to obtain a complete overview of the corrosion phenomena, also confirmed by post experiment observations. Considering the behavior of the analyzed system hypotheses have been suggested introducing an electrical equivalent circuit representing the single corrosion processes. The capacitive and resistive phenomena resulted influenced in their values and distributions by the mechanical state of the alloy.